2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography/computed tomography imaging evaluation of esophageal cancer

A computational approach for analysis of intratumoral heterogeneity and standardized uptake value in PET/CT images1

BACKGROUND

By providing both functional and anatomical information from a single scan, digital imaging technologies like PET/CT and PET/MRI hybrids are gaining popularity in medical imaging industry. In clinical practice, the median value (SUVmed) receives less attention owing to disagreements surrounding what defines a lesion, but the SUVmax value, which is a semi-quantitative statistic used to analyse PET and PET/CT images, is commonly used to evaluate lesions.

OBJECTIVE

This study aims to build an image processing technique with the purpose of automatically detecting and isolating lesions in PET/CT images, as well as measuring and assessing the SUVmed.

METHODS

The pictures are separated into their respective lesions using mathematical morphology and the crescent region, which are both part of the image processing method. In this research, a total of 18 different pictures of lesions were evaluated.

RESULTS

The findings of the study reveal that the threshold is satisfied by both the SUVmax and the SUVmed for most of the lesion types. However, in six instances, the SUVmax and SUVmed values are found to be in different courts.

CONCLUSION

The new information revealed by this study needs to be further investigated to determine if it has any practical value in diagnosing and monitoring lesions. However, results of this study suggest that SUVmed should receive more attention in the evaluation of lesions in PET and CT images.

Utility of near-infrared fluorescence imaging with indocyanine green in resection of oesophageal squamous cell carcinoma: A literature review and a case report

BACKGROUND

Surgery remains the main primary treatment for non-advanced oesophageal cancer. Conventional thoracotomy and laparotomy can result in severe trauma, slow recovery, more complications, low quality of life, and reduced survival outcomes. Laparoscopic surgery has reduced the above-mentioned problems. However, some challenges remain associated with this approach, such as lymphadenectomy, anastomotic leakage, and inadequate surgical margins. Near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) in combination with laparoscopic surgery, provides real-time navigation throughout the entire surgical procedure.

CASE PRESENTATION

A middle-aged male patient presented to our health centre with progressive dysphagia for > 2 months. Endoscopy and biopsy revealed oesophageal squamous cell carcinoma 34 cm from the incisors (tumour node metastasis classification (TNM) T3N1M0 IIIB). ICG imaging fluorescence laparoscopic surgery was successfully performed to complete the oesophagectomy and oesophageal and tubular stomach anastomosis by accurately locating the lesion, retaining adequate upper and lower margins, visually dissecting the lymph nodes, and testing the anastomotic blood supply. The postoperative TNM stage was T2N0M0 ⅡA. The patient recovered quickly without complications. Postoperative chemotherapy was administered. After three years of follow-up, the patient had no recurrence or complications.

CONCLUSIONS

Fluorescence laparoscopy provides an excellent surgical treatment modality for patients with oesophageal cancer.

Metabolic and Immunological Subtypes of Esophageal Cancer Reveal Potential Therapeutic Opportunities

BACKGROUND

Esophageal cancer has the sixth highest rate of cancer-associated deaths worldwide, with many patients displaying metastases and chemotherapy resistance. We sought to find subtypes to see if precision medicine could play a role in finding new potential targets and predicting responses to therapy. Since metabolism not only drives cancers but also serves as a readout, metabolism was examined as a key reporter for differences.

METHODS

Unsupervised and supervised classification methods, including hierarchical clustering, partial least squares discriminant analysis, k-nearest neighbors, and machine learning techniques, were used to discover and display two major subgroups. Genes, pathways, gene ontologies, survival, and immune differences between the groups were further examined, along with biomarkers between the groups and against normal tissue.

RESULTS

Esophageal cancer had two major unique metabolic profiles observed between the histological subtypes esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). The metabolic differences suggest that ESCC depends on glycolysis, whereas EAC relies more on oxidative metabolism, catabolism of glycolipids, the tricarboxylic acid (TCA) cycle, and the electron transport chain. We also noted a robust prognostic risk associated with COQ3 expression. In addition to the metabolic alterations, we noted significant alterations in key pathways regulating immunity, including alterations in cytokines and predicted immune infiltration. ESCC appears to have increased signature associated with dendritic cells, Th17, and CD8 T cells, the latter of which correlate with survival in ESCC. We bioinformatically observed that ESCC may be more responsive to checkpoint inhibitor therapy than EAC and postulate targets to enhance therapy further. Lastly, we highlight correlations between differentially expressed enzymes and the potential immune status.

CONCLUSION

Overall, these results highlight the extreme differences observed between the histological subtypes and may lead to novel biomarkers, therapeutic strategies, and differences in therapeutic response for targeting each esophageal cancer subtype.

Identification of a RNA-Seq Based 8-Long Non-Coding RNA Signature Predicting Survival in Esophageal Cancer

Background

Accumulating evidence suggests the involvement of long non-coding RNAs (lncRNAs) as oncogenic or tumor suppressive regulators in the development of various cancers. In the present study, we aimed to identify a lncRNA signature based on RNA sequencing (RNA-seq) data to predict survival in esophageal cancer.

Material/Methods

The RNA-seq lncRNA expression data and clinical information were downloaded from The Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs were screened out between esophageal cancer and normal tissues. Univariate and multivariate Cox regression analysis were performed to establish a lncRNA-related prognostic model. Receiver operating characteristic (ROC) analysis was conducted to test the sensitivity and specificity of the model. GO (gene ontology) functional and KEGG pathway enrichment analyses were performed for mRNAs co-expressed with the lncRNAs to explore the potential functions of the prognostic lncRNAs.

Results

A total of 265 differentially expressed lncRNAs were identified between esophageal cancer and normal tissues. After univariate and multivariate Cox regression analysis, eight lncRNAs (GS1-600G8.5, LINC00365, CTD-2357A8.3, RP11-705O24.1, LINC01554, RP1-90J4.1, RP11-327J17.1, and LINC00176) were finally screened out to establish a predictive model by which patients could be classified into high-risk and low-risk groups with significantly different overall survival. Further analysis indicated independent prognostic capability of the 8-lncRNA signature from other clinicopathological factors. ROC curve analysis demonstrated good performance of the 8-lncRNA signature. Functional enrichment analysis showed that the prognostic lncRNAs were mainly associated with esophageal cancer related biological processes such as regulation of glucose metabolic process and amino acid and lipids metabolism.

Conclusions

Our study developed a novel candidate model providing additional and more powerful prognostic information beyond conventional clinicopathological factors for survival prediction of esophageal cancer patients. Moreover, it also brings us new insights into the molecular mechanisms underlying esophageal cancer.

Diagnostic Performance of ¹⁸F-FDG PET and PET/CT for the Detection of Recurrent Esophageal Cancer After Treatment with Curative Intent: A Systematic Review and Meta-Analysis

The aim of this study was to assess the diagnostic performance of (18)F-FDG PET and integrated (18)F-FDG PET/CT for diagnosing recurrent esophageal cancer after initial treatment with curative intent.

METHODS

The PubMed, Embase, and Cochrane library were systematically searched for all relevant literature using the key words "(18)F-FDG PET" and "esophageal cancer" and synonyms. Studies examining the diagnostic value of (18)F-FDG PET or integrated (18)F-FDG PET/CT, either in routine clinical follow-up or in symptomatic patients in whom recurrence of esophageal cancer was suspected, were deemed eligible for inclusion. The primary outcome was the presence of recurrent esophageal cancer as determined by histopathologic biopsy or clinical follow-up. Risk of bias and applicability concerns were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Sensitivities and specificities of individual studies were meta-analyzed using bivariate random-effects models.

RESULTS

Eight eligible studies were included for meta-analysis, comprising 486 patients with esophageal cancer who underwent (18)F-FDG PET or PET/CT after previous treatment with curative intent. The quality of the included studies assessed by the QUADAS-2 tool was considered reasonable; there were few concerns with regard to the risk of bias and applicability. Integrated (18)F-FDG PET/CT and standalone (18)F-FDG PET were used in 4 and 3 studies, respectively. One other study analyzed both modalities separately. In 4 studies, (18)F-FDG PET or PET/CT was performed as part of routine follow-up, whereas in 4 other studies the diagnostic test was performed on indication during clinical follow-up. Pooled estimates of sensitivity and specificity for (18)F-FDG PET and PET/CT in diagnosing recurrent esophageal cancer were 96% (95% confidence interval, 93%-97%) and 78% (95% confidence interval, 66%-86%), respectively. Subgroup analysis revealed no statistically significant difference in diagnostic accuracy according to type of PET scanner (standalone PET vs. integrated PET/CT) or indication of scanning (routine follow-up vs. on indication).

CONCLUSION

(18)F-FDG PET and PET/CT are reliable imaging modalities with a high sensitivity and moderate specificity for detecting recurrent esophageal cancer after treatment with curative intent. The use of (18)F-FDG PET or PET/CT particularly allows for a minimal false-negative rate. However, histopathologic confirmation of (18)F-FDG PET- or PET/CT-suspected lesions remains required, because a considerable false-positive rate is noticed.

Significance of 18F-Fluorodeoxyglucose Uptake at the Gastroesophageal Junction: Comparison of PET to Esophagogastroduodenoscopy

BACKGROUND

Positron emission tomography-computed tomography (PET/CT) occasionally reveals unexpected uptake of (18)F-fluorodeoxyglucose ((18)F-FDG) at the gastroesophageal junction (GEJ). The aim of this study was to determine the importance of unexpected (18)F-FDG uptake at the GEJ on PET/CT by correlating this finding with endoscopy results.

METHODS

We reviewed medical records from June 2009 to October 2012 to identify patients in our Veterans Affairs Medical Center who had an esophagogastroduodenoscopy (EGD) performed within 6 months of a PET/CT. Metabolic activity at the GEJ was quantified with standardized uptake values (SUV) and correlated with EGD and histopathology results.

RESULTS

A total of 219 patients were identified and assigned to one of five groups based upon EGD findings: esophageal malignancy (n = 34), esophagitis (n = 21), Barrett's esophagus (n = 8), other non-malignant disorders (n = 5), and normal (n = 151). The mean SUV Max for the groups was 6.72, 2.47, 2.40, 3.48, and 2.06, respectively. SUV Max and SUV Mean were significantly higher in the esophageal malignancy group than in all other groups (p < 0.001). SUV for patients with high-grade esophagitis was greater than in patients with low-grade esophagitis. A SUV Max ≥ 3.5 was found to predict necessity for EGD with a positive predictive value of 79 %. A SUV Max ≤ 2.2 yielded a negative predictive value of 86 %.

CONCLUSION

Differentiation between benign and potentially significant disease at the GEJ may be possible with quantification of incidental (18)F-FDG uptake at PET/CT. Our results suggest thresholds that may help determine need for further endoscopic evaluation in patients with abnormal metabolic activity at the GEJ.

Value of EUS in Determining Curative Resectability in Reference to CT and FDG-PET: The Optimal Sequence in Preoperative Staging of Esophageal Cancer?

BACKGROUND

F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the optimal sequence in staging esophageal cancer has not been investigated adequately.

METHODS

The staging records of 216 consecutive operable patients with esophageal cancer were reviewed blindly. Different staging strategies were analyzed, and the likelihood ratio (LR) of each module was calculated conditionally on individual patient characteristics. A logistic regression approach was used to determine the most favorable staging strategy.

RESULTS

Initial EUS results were not significantly related to the LRs of initial CT and FDG-PET results. The positive LR (LR+) of EUS-fine-needle aspiration (FNA) was 4, irrespective of CT and FDG-PET outcomes. The LR+ of FDG-PET varied from 13 (negative CT) to 6 (positive CT). The LR+ of CT ranged from 3-4 (negative FDG-PET) to 2-3 (positive FDG-PET). Age, histology, and tumor length had no significant impact on the LRs of the three diagnostic tests.

CONCLUSIONS

This study argues in favor of PET/CT rather than EUS as a predictor of curative resectability in esophageal cancer. EUS does not correspond with either CT or FDG-PET. LRs of FDG-PET were substantially different between subgroups of negative and positive CT results and vice versa.

Imaging and 'omic' methods for the molecular diagnosis of cancer

Molecular imaging methods can noninvasively detect specific biological processes that are aberrant in cancer, including upregulated glycolytic metabolism, increased cellular proliferation and altered receptor expression. PET using the glucose analogue 18F-fluoro-2-deoxyglucose, which detects the increased glucose uptake that is a characteristic of tumor cells, has been widely used in the clinic to detect tumors and their responses to treatment; however, there are many new PET tracers being developed for a wide range of biological targets. Magnetic resonance spectroscopy (MRS), which can be used to detect cellular metabolites, can also provide prognostic information, particularly in brain, breast and prostate cancers. An emerging technique, which by hyperpolarizing 13C-labeled cell substrates dramatically enhances their sensitivity to detection, could further extend the use of MRS in molecular imaging in the clinic. Molecular diagnostics applied to serum samples or tumor samples obtained by biopsy, can measure changes at the individual cell level and the underlying changes in gene or protein expression. DNA microarrays enable high-throughput gene-expression profiling, while mass spectrometry can detect thousands of proteins that may be used in the future as biomarkers of cancer. Probing molecular changes will aid not only cancer diagnosis, but also provide tumor grading, based on gene-expression analysis and imaging measurements of cell proliferation and changes in metabolism; staging, based on imaging of metastatic spread and elevation of protein biomarkers; and the detection of therapeutic response, using serial molecular imaging measurements or monitoring of serum markers. The present article provides a summary of the molecular diagnostic methods that are currently being trialed in the clinic.

Early detection of recurrence after endoscopic treatment for early gastric cancer

OBJECTIVE

Although there have been many reports regarding clinical outcomes of endoscopic treatment for early gastric cancer (EGC), little is known about detection of recurrence after endoscopic submucosal dissection (ESD). This study aims to clarify the clinical value of serological marker or imaging tools, including conventional CT and PET-CT scans, in detecting recurrent gastric cancer after ESD in Korea.

MATERIAL AND METHODS

From July 2004 to March 2008, 212 patients who had received ESD for EGC were enrolled in the study. For preoperative staging, conventional CT and PET-CT scans were performed in 141 patients, and for detection of recurrence of cancer, conventional CT, PET-CT scans and tumour marker; CEA, CA19-9, AFP were checked in 165 patients.

RESULTS

The local recurrence rate was 4.7% (10/212) during the study period. At 9 months after endoscopic treatment, 3 cases recurred. Four showed recurrence at 12 months, 2 at 18 months and 1 at 24 months. The positive rate was 7.1% (10/141) in conventional CT and 0% (0/24) in PET-CT scans for preoperative staging. Conventional CT and PET-CT scans could not detect local recurrence of cancer during the follow-up period. Tumour markers did not show any significant correlation with recurrence of cancer.

CONCLUSIONS

The study suggests that conventional CT, PET-CT scans and tumour marker have no role in the primary surveillance of early gastric cancer and/or in detecting recurrence after endoscopic treatment. For early diagnosis of recurrence after endoscopic treatment, a biopsy specimen from the endoscopic examination has to be obtained at regular intervals.

Feasibility of using 18F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer

AIM: To investigate the feasibility of using ¹⁸F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer.

METHODS: The clinical records of 40 advanced gastric cancer patients who underwent ¹⁸F-FDG PET/CT before treatment were reviewed retrospectively. Of these patients, 14 patients underwent radical gastrectomy, and the other patients underwent chemotherapy or palliative gastrectomy. The lymph nodes were classified into two groups (N₁ + N₂ group and N₃ group) based on anatomic sites. Lymph node metastasis was assessed on group basis. All PET/CT images were interpreted according to visual evaluation and standardized uptake values (SUVs).

RESULTS: The diagnostic sensitivity of ¹⁸F-FDG PET/CT, PET and CT for primary tumors was 97.5%, 65% and 90%, respectively. The sensitivity, specificity, and accuracy of 18F-FDG PET/CT for N₁ + N₂ metastases were 71.4%, 77.8% and 85.7%, respectively, while the sensitivity of PET/CT for N₃ metastases was 100%. PET/CT detected 21 cases of metastases undetected by routine method. Accordingly, the TNM stage of tumors was upgraded in 40% of patients.

CONCLUSION: It is feasible to use ¹⁸F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer, and the diagnostic outcomes revealed by PET/CT may have a clinically significant impact on the choice of initial therapy.

Prediction of metastatic disease and survival in patients with gastric and gastroesophageal junction tumors: the incremental value of PET-CT over PET and the clinical role of primary tumor volume measurements

RATIONALE AND OBJECTIVES

To investigate the accuracy of M staging (staging of metastatic disease) in esophageal carcinoma based on a visual interpretation and based on tumor volume measurements on positron emission tomography (PET) computed tomography (CT).

MATERIALS AND METHODS

Fifty-nine untreated patients with gastroesophageal junction tumors were enrolled, including 36 subcardial gastric tumors (type III according to Siewert classification) and 23 adenocarcinomas of the cardia (AEG, type II Siewert). Patients were grouped in metastasis free (M0 stage, n = 34) and metastatic stages (M1 stage, n = 25). Tumor volume and mean and maximum standardized uptake value were measured on PET-CT. The accuracy of these quantitative tumor volume parameters in distinguishing metastasis-free tumors (M0 stage) from metastatic stages (M1 stage) was compared to the accuracy of a visual analysis with fused PET-CT. Furthermore, accuracy of PET-CT was compared to PET reviewed side by side with CT in a lesion-based analysis of 84 distant metastatic sites.

RESULTS

In the visual interpretation, PET-CT (accuracy 88%, 74/84) was more accurate than PET (accuracy 78%, 66/84; P = .008) in characterizing the 84 potential metastatic sites in the 59 patients. Among the tumor parameters, the PET-CT tumor volume was the most accurate predictor of M1 stage and overall survival. With a threshold of 39 mL, PET-CT volume was able to predict M1 stage disease with a sensitivity of 96% and a specificity of 85%. The accuracy of M-staging was increased further when combining tumor volume measurements with the results from the visual analysis (combined results: sensitivity 96%, specificity 94%).

CONCLUSIONS

PET-CT was more accurate than PET (reviewed side by side with CT) in characterizing distant metastatic sites of gastroesophageal junction carcinomas. The highest accuracy for M-staging was obtained when combining the results of the visual analysis with the results from primary tumor volume measurements. Primary tumor volume was shown to be an independent prognostic factor.

Subcutaneous metastasis from an occult esophageal cancer detected by PET-CT

We describe a unique case of an occult esophageal cancer patient without any significant symptomatology, which initially presented with a subcutaneous metastasis in the thigh. Eventually, FDG PET-CT unmasked the primary tumor of unknown origin.

Positron emission tomography changes management and prognostic stratification in patients with oesophageal cancer: results of a multicentre prospective study

OBJECTIVES

The aims of this study were (1) to determine the incremental information provided by (18)F-FDG positron emission tomography (PET) in staging patients with oesophageal cancer, and (2) to determine the impact of PET staging on post-PET clinical management of oesophageal cancer, and on prognosis.

METHODS

In a multicentre, single-arm open study, patients with proved oesophageal cancer without definite distant metastases and regarded as suitable for potentially curative treatment were examined by PET. Clinicians were requested to supply a management plan before and another plan after being supplied with the PET scan results. Patients were followed for at least 1 year for outcome analysis.

RESULTS

A total of 129 patients (104 men, mean age 67 y) were recruited. PET detected additional sites of disease in 53 patients (41%). Significant changes in management (high or medium impact) were observed in 38% of patients, primarily as a result of identifying additional sites of disease and/or confirming previously equivocal regional and distant metastases. Progression-free survival was significantly shorter in patients found to have additional lesions on PET (p < 0.05), but was not related to SUV(max).

CONCLUSION

These findings demonstrate the significant impact of PET on the clinical management of patients with newly diagnosed oesophageal carcinoma, and on prognostic stratification of these patients.

Impact of the introduction of integrated PET-CT into the preoperative staging pathway of patients with potentially operable oesophageal carcinoma

AIM

To retrospectively evaluate the role of integrated positron emission tomography computed tomography (PET-CT) in oesophageal carcinoma staging, in predicting prognosis and its influence on surgical management.

MATERIALS AND METHODS

Twenty-five consecutive patients with potentially operable, biopsy-proven oesophageal malignancy who undergoing PET-CT from September 2004 to April 2007 were included in this study. Chi-square and Fisher's exact tests were used to compare the accuracy of N staging with PET-CT and CT/endoscopic ultrasound (EUS) using postoperative loco-regional nodal histology as the reference standard. The prognostic value of primary tumour maximum standardized uptake value (SUVmax) was derived using logistic regression.

RESULTS

Seventeen men and eight women with a mean age of 62 years were studied. All tumours showed abnormal 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) uptake. Fifteen patients underwent surgical resection. There was high concordance between N staging at CT/EUS (14/15) and final histology. PET-CT N staging was discordant with final nodal histology in over half of the patients (8/15). PET-CT detected occult metastases in three patients (12%) that were not identified on CT and new synchronous tumours in two patients (8%). Patient management was altered in 10 patients (40%) as a direct result of PET-CT. No statistically significant association was observed between SUVmax and clinical outcome (p=0.65).

CONCLUSION

Integrated PET-CT has a significant incremental value over conventional staging investigations mainly in the detection of distant metastases and synchronous tumours and frequently impacts on patient management.

18F-DG PET/CT in detection of recurrence and metastasis of colorectal cancer

AIM: To evaluate the value of ¹⁸F-DG PET/CT in detecting recurrence and/or metastasis of colorectal cancer (CRC).

METHODS: Combined visual analysis with semiquantitative analysis, the ¹⁸F-DG PET/CT whole-body imaging results and the corresponding clinical data of 68 postoperative CRC patients including 48 male and 20 female with average age of 58.1 were analyzed retrospectively.

RESULTS: Recurrence and/or metastasis were confirmed in 56 patients in the clinical follow-up after the PET/CT imaging. The sensitivity of PET/CT diagnosis of CRC recurrence and/or metastasis was 94.6%, and the specificity was 83.3%. The positive predictive value (PPV) was 96.4% and the negative predictive value (NPV) was 76.9%. PET/CT imaging detected one or more occult malignant lesions in 8 cases where abdominal/pelvic CT and/or ultrasonography showed negative findings, and also detected more lesions than CT or ultrasonography did in 30.4% (17/56) cases. Recurrence and/or metastasis was detected in 91.7% (22/24) cases with elevated serum CEA levels by ¹⁸F-DG PET/CT imaging.

CONCLUSION: ¹⁸F-DG PET/CT could detect the recurrence and/or metastasis of CRC with high sensitivity and specificity.

PET-CT in clinical oncology

Anatomic imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have been used for many years in clinical oncology. The emergence of positron emission tomography (PET) more than a decade ago was a major breakthrough in the early diagnosis of malignant lesions, as it was based on tumour metabolism and not on anatomy. The merger of both techniques into one thanks to PET-CT cameras has made this technology the most important tool in the management of cancer patients. PET/CT with 18F-FDG is increasingly being used for staging, restaging and treatment monitoring for cancer patients with different types of tumours (lung, breast, colorectal, lymphoma, melanoma, head and neck etc.). At many institutions, PET/CT has replaced separately acquired PET and CT examinations for many oncologic indications. This replacement has occurred despite the fact that only a relatively small number of well designed prospective studies have verified imaging findings against the gold standard of histopathologic tissue evaluation. However, a large number of studies have used acceptable reference standards, such as pathology, imaging and other clinical follow-up findings, for validating PET/CT findings. The impact on the management of patients and the benefits from the information obtained from this anatomo-metabolic procedure justify the term "clinical oncology based on PET-CT" as a new concept to be applied in clinical practice.